TWO-DIMENSIONAL SIMULATIONS OF FU ORIONIS DISK OUTBURSTS

Journal Article · Mon Aug 10 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/701/1/620; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313666

Zhaohuan, Zhu; Hartmann, Lee ^[1]; Gammie, Charles ^[2]

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1. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States)
2. Department of Astronomy, University of Illinois Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States)

We have developed time-dependent models of FU Ori accretion outbursts to explore the physical properties of protostellar disks. Our two-dimensional, axisymmetric models incorporate full vertical structure with a new treatment of the radiative boundary condition for the disk photosphere. We find that FU Ori-type outbursts can be explained by a slow accumulation of matter due to gravitational instability. Eventually, this triggers the magnetorotational instability, which leads to rapid accretion. The thermal instability is triggered in the inner disk, but this instability is not necessary for the outburst. An accurate disk vertical structure, including convection, is important for understanding the outburst behavior. Large convective eddies develop at the transition region between the thermal instability high-low states in the inner disk. The models are in agreement with Spitzer IRS spectra and also with peak accretion rates and decay timescales of observed outbursts, though some objects show faster rise timescale. We also propose that convection may account for the observed mild-supersonic turbulence and the short-timescale variations of FU Orionis objects.

• OSTI ID: 21313666
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 701; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ACCRETION DISKS
AXIAL SYMMETRY
BOUNDARY CONDITIONS
GRAVITATIONAL INSTABILITY
MAIN SEQUENCE STARS
MATTER
PHOTOSPHERE
SIMULATION
TIME DEPENDENCE
TURBULENCE
TWO-DIMENSIONAL CALCULATIONS